Powdered laundry detergents have typically been provided in cartons fabricated from paperboard. Generally, such cartons are provided with die-cut perforations in the paperboard along which the consumer makes an opening in the carton.
Once these perforations are ruptured and an opening made in the carton, the large and irregular shape of the aperture formed makes it difficult to control the product during pouring. Furthermore, openings in the paperboard are not reclosable to a satisfactory degree. As a result, a tendency exists for the product to spill undesirably from the carton if tipped, and especially during transport. Moreover, products which are sensitive to moisture pick-up tend to cake because of the exposed opening.
One attempt to provide a solution to this problem has been to provide a metal spout which in use is a hinged, three-sided structure mounted on a carton sidewall. These are difficult to seal initially for shipment, are generally not well adapted to dispensing of large usage amounts for products such as laundry detergent granules or the like and are expensive to manufacture and apply to cartons.
Another attempt to solve the aforementioned problems has involved the use of plastic. Plastic fitments have been prepared which can be adhesively attached to the carton. It is generally desirable for detergent manufacturers that the fitment be affixed when the paperboard carton is in a flat, tubular form prior to erection of the carton. However, according to Gunn U.S. Pat. No. 4,732,315, when a thin, plastic fitment is affixed to the carton in its flat, tubular form problems may arise during stacking of the tubes due to an imbalance in the otherwise flat cartons caused by the extra thickness of the fitment. Gunn discloses a plastic closure device having an aperture configured in a pentagonal, "home plate" shape said to have rounded corners, which is balanced by means integral with the carton. For instance, the means may comprise score lines which are thickened to offset the extra thickness of the fitment. The tapered pointed end of Gunn's fitment is said to assist in properly directing the product stream.
Further disadvantages attendant to the use of plastic fitments in general are environmental problems due to the non-biodegradability of these materials. More importantly, the plastic component interferes with the recyclability of the paperboard carton after consumer use.
U.S. Pat. No. 4,650,078 to Desmond et al. discloses a closure in which a plug is attached to the underside of an external hinged flap side section. When the hinge flap side section is pulled away from a side wall panel, the plug attached to the side section disengages from a minor side wall panel to provide an opening in the side wall panel.
The Desmond et al. closure is a "push-in" friction fit type closure which is subject to opening undesirably. Moreover, no provision is made to facilitate grasping of the closure by the consumer. In addition, since the Desmond et al. design features only a partial height side section, there may be uneven roll-down which can further cause imbalance on stacking and there may be less strength added to the erect carton than if the side section were full height.
It is known in the art to use an extended glue panel behind a side panel and to include an opening in both the side and glue panels (see, for example, U.S. Pat. No. 3,549,079). No closure flap appears to be disclosed by this reference.
U.S. Pat. No. 3,563,447 (Katzenmeyer) teaches a carton in which removable material may be disengaged from a panel to which it is initially secured and then re-engaged into the recess left by the material removed. The resealable closure is on one panel and uses a different configuration than that of the invention. Namely, the Katzenmeyer closure is hinged along the vertical score on the side of the carton, and features a relatively small, off-centered, "racetrack-shaped" opening. Moreover, the tuck-in tab feature does not utilize the opening itself, but rather the tab feature is separate and positioned between the hinge and the opening. It is a critical feature of this design that the inside panel be extended only one-half the distance across the sidewall so that the tuck-in tab can function.
U.S. Pat. No. 4,142,635 (Capo et al.) also involves a different fitment. The carton described is folded differently than any other detergent carton now in use (e.g., top panel 17 and bottom panel 11 are normally sidewalls). Changeover to this design would involve major machine modifications for any manufacturer.
Additionally, the Capo, et al. closure on an erected carton would involve a top opening construction which would be difficult to seal adhesively at high speeds in a production operation. Besides the need for precise adhesive application around the opening, separate equipment would be needed to seal the side panel pieces which consist of four thicknesses. This would probably result in increased downtime and increased scrap due to an increased frequency of poor quality seals.
None of these patents show a combination of a novel, reclosable pouring opening as described below in which the closure has been coated with a thin protective polymeric coating.
Thus, it would be extremely desirable to find a carton which provides a secure novel closure not made of metal or of plastic, which can be securely resealed quite readily, which does not cause imbalance on stacking, which can be made more economically than prior art cartons, which can be easily sealed with existing equipment a high speeds, and to which has been added a thin polymeric coating to protect the closure from wetness and extend the useful life of the closure.